ABSORPTION BY ROOTS
Frequently Tested Topics:
Osmosis, Endosmosis, Exosmosis
Experiments on Osmosis
Turgidity, Flaccidity, Plasmolysis
Conduction of Water in Root Hair
*Note that other aspects of the chapter are equally important.
Structure of Root Hair
Experiment Demonstrating Osmosis
Turgid, Flaccid, and Plasmolysed Cells
Conduction of Water in a Root Hair and Xylem Vessels
Important Past Questions:
Name the following:
i) The process by which root hairs absorb water from the soil. (2017)
ii) The process of uptake of mineral ions against the concentration gradient using energy from the cell. (2015)
Explain the following term:
Correct the following statement by changing the underlined words.
i) The cell sap of root hair is hypotonic. (2018)
ii) Free movement of solutes in and out of the cell takes place across the cell membrane. (2017)
Differentiate between the following on the basis of what is given in the brackets:
Hypotonic solution and Hypertonic solution (condition of a plant cell when placed in them)
Account for the following:
Wilted lettuce leaves become crisp/firm when placed in cold water for a while.
____________ is the phenomenon of contraction of the cytoplasm from the cell wall.
Give biological terms for the following:
Movement of molecules of a substance from their higher concentration to lower concentration when they are in direct contact.
DIAGRAM BASED QUESTIONS
The figure given below is a diagrammatic representation of a part of the cross section of the root in the root hair zone. Study the same and then answer the question that follow:
i) Name the parts indicated by the guidelines 1 to 4.
ii) Which is the process that enables the passage of water from the soil into the root hair ?
iii) Name the pressure that is responsible for the movement of water in the direction indicated by the arrows. Define it.
iv) Due to an excess of this pressure sometimes drops of water are found along the leaf margins of some plants especially in the early mornings. What is the phenomenon called ?
v) Draw a well labelled diagram of the root hair cell as it would appear d an excess of fertilizer is added to the soil close to it.